/Engine/Source/Runtime/InteractiveToolsFramework/Public/BaseTools/BaseBrushTool.h
OnDragStart()defines the starting location of an adjustmentOnDragUpdate()adjusts the brush strength and radius based on the magnitude of the screen coordinate delta in the vertical and horizontal directions respectively.
class UBrushAdjusterInputBehavior : public [UAnyButtonInputBehavior](API\Runtime\InteractiveToolsFramework\BaseBehaviors\UAnyButtonInputBehavior)